Air flight control levers, such as those used to control the throttle, the flaps or the speed brake of an airplane, include different tactile resistance mechanisms which assist a pilot in operating the control levers. These mechanisms are designed to place resistance on the control levers which provides the pilots with greater control over the airplane.
One type of mechanism places a constant resistance upon the control lever which is felt over the entire "throw" of the lever. This resistance is to insure that a certain amount of force is required to move the control lever, while allowing the pilot to "feel" the lever as it moves within its housing. Another type of resistance mechanism used with control levers is a detent. A detent places a greater amount of resistance upon the control lever at a specific point, and is used to tactually signal the pilot before the control lever passes through a cross-over point. For example, in jet fighters, there is a detent in the throttle mechanism to let the pilot know, as the throttle is advanced, that a point is reached, past which the afterburners "kick in", causing the jet to rapidly increase speed.
The differences in pilots' flying styles and techniques require that the resistance placed upon the control lever be adjustable to meet the desires of each individual pilot. In current control levers, however, the detents typically are not adjustable. Thus, when the resistance or "feel friction" of the control lever is adjusted to a low level, the resistance on the detent remains unchanged at a high level. The pilot must exert extra force to move the lever over the detent, creating a serious danger that "overshoot" will occur. For example, if the pilot must apply eight pounds of pressure to pass the detent, but encounters only two pounds of resistance from the "feel friction" on the lever beyond the detent, the pilot is likely to overshoot the detent point as the lever is moved past the eight pound resistance of the detent.
In the case of a jet fighter throttle, overshoot could result in unwanted and unexpected increases in speed. Overshoot may similarly occur in brake and flap controls which incorporate detents to alert the pilot of pivotal cross-over points. Thus, as in the case of the throttle control, if the "feel friction" on the lever is adjusted to a low level of resistance, overshoot can occur which may cause a plane to lose air speed excessively.
While many currently available flight controls include as standard equipment mechanisms which allow the "feel friction" to be adjusted, these controls fail to provide an adjustable detent mechanism and fail to address the problems and dangers associated with "overshoot," as discussed above.
Accordingly, an object of the present invention is to provide an adjustable tactile resistance detent mechanism which minimizes or eliminates the danger of overshoot.
Another object of the present invention is to provide an adjustable tactile resistance detent mechanism which varies in proportion to the adjustable feel friction in the air flight control levers.
These and other objects and advantages of the invention will become apparent from the following description and drawings.